Telephone-exchange system



R. S. WILBUR.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION man SEPT- 25. 1917.

1 3 1 2,77 3 r Patented Aug. 12, 1919.

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' UNITED STATES PATENT OFFICE.

RAY S. WILBUR, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Aug. 12, 1919.

Application filed September 25, 1917. Serial No. 193,097.

To all whom it may concern Be it known that I, RAY S. WILBUR, a citizenof the United States, residing at Jersey City, in the county of Hudsonand State of New Jersey, have invented certain new and usefulImprovements in Telephone- Exchange Systems, of which the following is afull, clear, concise, and exact description.

This invention relates to telephoneexchange systems and has for its0l)]60t the production of improved signaling means for such systems.

In accordance with this invention, a llnk circuit employed forinterconnectlng telephone lines is provided with a fast operating and aslow operating relay which cooperate with a supervisory relay to connectinterrupter mechanism; in c1rc u1t w th a supervisory lamp to cause theintermlttent operation thereof, thereby to furnish a signal to theoperator that a recall has been made on one of the connected telephonelines.

For a more complete understanding of this invention reference should behad to.

the following description considered in connection with the accompanylngdrawlng illustrating one embodiment thereof.

There is shown in the drawing a local subscribers telephone line A whichterm nates at a local switchboard X at which is located the incoming endof a toll switching trunk circuit D. There is also shown a toll line Bwhich terminates at a tollswitch board Y at which is located theoutgoing end of the toll switching trunk circuit D and a toll cordcircuit C which s employed for forming a portion of the connectionbetween the toll line B and the local line A. The central officeapparatus located to the right of the dotted line 2-9-2 is preferablylocated in the toll office, while that shown to the left of the llne 2-2is preferably located at the local central oflice. The apparatus shownwithin the dotted rectangle E is common to a plurality of cord circuits.

In systems of the character disclosed in the drawing, the toll operatorin charge of the toll cord circuit C usually receives from a recordingoperator, also located at the toll,

' office, a ticket giving the information as to the calling subscriberandthe called party-- either by number or name. The toll operator maythen connect the operators telephone set with an order wire circuit (notshown) which extends from the toll board to a toll switching operatorsposi-. tion at the local board, the latter operator being in charge ofthe incoming end of to be used. At anyrate, the toll switching operatorinserts the ping of the proper in coming toll switching trunk into ajack of the desired local line and the toll operator releases the orderwire key and inserts plug 5 of cord circuit G into the outgoing jack ofthe proper toll switching trunk. Trunk circuit D merely serves to extendthe telephone line A to the toll switchboard Y, and for the purpose ofthe present invention, the trunk circuit D may be considered as aportion of the telephone line A which may therefore be considered asterminating at switchboard Y.

The toll operator may designate the Assuming the assigned toll switchingcoining end thereof in jack 7 of line A,

causes the operation of relay 8 of the trunk circuit and cut-oft relay 9of the line circuit. If the toll operator has not already inserted plug5 into jack 10- of the trunk circuit, lamp 11, associated with theincoming end of the call wire circuit, will be lighted over a circuitfrom battery through the lamp 11, lower alternate contact of relay 8,resistance 12 and normal contact of relay 13 to ground. If the tolloperator inserts the plug 5 of cord circuit G into jack 10 before thetoll switching operator inserts plug 6 into jack 7, relay 13 is operatedover a circuit from battery through the left-hand Winding of relay 13,lower normal contact of relay 14, repeating coil winding 15, tipcontacts of jacklO and plug 5,

impedance coil 16, winding of relay 17,

impedance coil 18, ring contacts of plug 5 and jack 10, repeating coilwindlng 19, upper normal contact of relay 14, and the right-hand windingof relay 13 to ground. Relay 13, in operating, causes lamp 11 to lightover a circuit from battery through the lamp 11, lower normal contact ofrelay 8, upper winding of relay 14, and alternate contact of relay 13 toground.

Relay 14 is also operated over the circuit just traced. This relay inoperating completes a circuit through its lower alternate contact whichmaintains relay 13 operated when the hereinbefore traced circuit ofrelay 13 is opened at the normal contacts of relay 14. The operation ofthis relay 14 prevents the operation of relay 17 and the consequentlighting of supervisory lamp 22. The insertion of plug 5 into jack 10also causes the operation of relay 20 over a circuit from batterythrough the left-hand winding of relay 20, sleeve contacts of the plug 5and jack 10, and resistance 21 to ground.

Relay 20, in operatmg, completes a 011'- cuit for slow operating relay23, and fast operating relay 24. Relay 24, upon belng energized over acircuit from battery through the lamp 22'," right-hand winding of relay24 and left-hand contact of relay 20 to ground, opens its normal contactwhich is in circuit with slow operating relay 23, whereby this slowoperating relay 23 does not have time to attract its armatures and closeits contacts before its circuit is opened at the normal contact of relay24. The right-hand winding of relay 24 is of high resistance so thatlamp 22 Wlll not be lighted when in circuit with this high resistancewinding. The left-hand winding of this relay 24 is of low resistance sothat when the lamp 22 is included in circuit therewith, the lamp will belighted. Relay 20 in operating also causes the operation of relay 25which is a fast operating relay. Relay 26 is slow in operating, so thatit is not sufliciently energized to at tract its armature before relay25 attracts its armature and opens the circuit of relay 26.

If the toll operator inserts plug 5 into Jack 10 before the tollswitching operator inserts plug 6 into jack 7, the lighting of the lamp11 serves as a signal to the toll switching operator that the tolloperator has plugged into the proper toll swltchmg trunk. The tollswitching operator may then insert plug 6 into jack 7, whereupon relay 8operates, extinguishing the lamp 11 and causing the release of relay 14.Relay 14 in releasing causes the operation of relay 17 over thehereinbefore traced circuit. The lamp 22 is immediately lighted uponoperation of relay 17, and a short circuit is established for therighthand winding of relay 24, which thereupon releases its armatures.The release of the righthand armature causes the operation of the slowoperating relay 23 over a circuit from battery through the winding ofslow operating relay 23, contact 27 of listening key 23, normal contactof relay 23, normal contact of relay 24, and left-hand contact of relay20 to ground. Relay 23 in operating completes a locking circuit foritself, which may be traced from battery through the winding of relay23, contact 27 of listening key 28, lefthand alternate Contact of relay23, and lefthand contact of relay 20 to ground. The closure of theright-hand contact of relay 23 connects interrupter 29 to the left-handcontact of relay 24, which is now open. The lighting of lamp 22 servesas a ringing signal to the toll operator so that this operator may nowactuate ringing key 30 to connect a source of ringing current to theoutgoing end of the toll switching trunk D, whereupon relay 31 isoperated.

Relay 31 in operating causes the operation of relay 32 over a circuitfrom battery through the lower winding of relay 14, winding of relay 32and the contact of relay 31 to ground. Relay 32 in operating connects asource of ringing current 33 to the local telephone line A to cause theoperation of the call bell 34. Relay 14 is also operated over thecircuit just traced. Supervisory relay 17 is released by the actuationof the ringing key 30. After ringing current is impressed upon line Afor a short interval, the toll operator restores the ringing key tonormal position, whereupon relays 31 and 32 are released, therebydisconnecting the source of ringing current from line A. Relay 14 alsoreleases, causing the operation of relay 17 and the lighting of lampSubscriber A, in response to the operation of call bell 34, removes thereceiver from the switchhook, thereby causing the. operation ofsupervisory relay 35. Supervisory relay 35 in operating causes theoperation of relay 14 over a circuit from battery through the lowerwinding of relay 14, contact of relay 35, upper winding of relay 14, andalternate contact of relay 13 to ground. Relay 14 in operating firstestablishes a holding circuit for relay 13, and then opens its normalcontacts, thereby releasing relay 17, which in turn extinguishes thelamp 22. The release of relay 17 also removes the short-circuit from thehigh resistance winding of the right hand winding of relay 24, whereuponthis relay operates, connecting the interrupter 29 through the lowresistance winding of relay 24 to the lamp 22, which is thereuponintermittently lighted. The operator may then actuate.

listening key 28 to connect the operators telephone set to the talkingstrands of the cord circuit. The operation of listening key 28, opensits contact 27, which is in the locking circuit of relay 23. Relay 23 isthereupon released, disconnecting the interrupter from circuit relationwith lamp 22. The lamp is thereby efi'aced.

The operator may now converse with the subscriber of local line A todetermine whether the incoming end of the toll switching trunk has beenconnected with the proper line or to determine whether the partyanswering is the particular party desired. After being assured that itis either the correct number or the particular party desired, theoperator instructs the local party to wait until connection is completedwith the toll line. The listening key 28 may then be restored to normalposition and plug 40 inserted into jack 41. Cut-oft relay 42 isthereupon operated to disconnect line relay 13 from the line. The tolloperator may then actuate ringing key 44. to connect the source ofringing current 45 with line B to cause the operation of call bell 16.The ringmg key is then restored to normal and the listening key actuatedin order to properly supervise the connection. In response totheoperation of call bell 4C6 the toll subscriber B removes the receiverfrom the switchhook and upon answering is advised by the toll operatorthat the local line A is connected for conversation. The operator maythen restore the listening key 28 to normal position.

If the toll subscriber B wishes to attract the attention of theoperator, a generator 47 located at the station on toll line B, isoperated, thereby causing the operation of relay 18 bridged across thecord circuit C. The operation of relay 4L8 releases relay 25, which inreleasing causes the operation of the slow operating relay 26 over acircuit from battery through the right-hand contact of relay 20, windingof relay 26 and lamp in parallel, contact of relay 25 and contact 49 oflistening key 28 to ground.

Relay 26 in operating establishes a locking circuit for itself throughits contact so that this relay remains operated and the lamp remainslighted after the relay 25 is again operated upon the release of thebridged relay 48. The operator upon observing the lighted condition oflamp 50 may actuate the listening key 28' to connect the operatorstelephone set across the cord circuit. The actuation of the listeningkey 28 opens contact 49, thereby releasing relay 26 and extinguishingthe lamp 50. Upon learning the wishes of the toll subscriber B, thelistening key may be restored to normal position.

At the conclusion of the conversation, subscriber A restores thereceiver to the switchhook and subscriber B rings off by operating thegenerator 4L7. The restoration of the receiver to the switchhook ofsubscriber A releases supervisory relay 35, whereupon relay letreleases, again establishing a circuit for supervisory relay 17 bridgedacross the cord circuit C. Relay 17 thereupon operates to light the lamp22, which now glows continuously. The operation of the generator l7causes the energization of slow operating relay 26, which then locks upto maintain the lamp 50 lighted. The con tinuous glowing of both of thelamps 22 and 50 serves as disconnect signals to the toll operator whomay then withdraw the plugs from the jacks, restoring all apparatus ofthe cord circuit C to normal position. The withdrawal of the plug 5 fromthe jack 10, causes the release of relay 13, whereupon the lamp 11 islighted to furnish a disconnect signal to the toll switching operator.The toll switching operator may thereupon wlthdraw the plug 6 from thejack 7, whereupon all apparatus associated with the line A- and tollswitching trunk D is restored to normal position.

If after the subscriber A restores the receiver to the switchhook andbefore the toll operator withdrew the plug 5 from the jack 10, the localsubscriber A again removes the receiver from the switchhook, the lamp 221s thereupon intermittently lighted to furnish a signal to the operatorthat subscriber A wishes to make a recall. This is accomplished in thefollowing manner.

Upon the operation of relay 17 when subscrlber A restores the receiverto the switchhook, a short circuit is established for the right-handwinding of relay 2a, which thereupon releases its armatures. Upon theclosure of the right contact of relay 24, relay 23 is operated andlocked up in the manner hereinbefore described. The interrupter 29 isnow connected with the lefthand open contact of relay 24: so that whenrelay 17 releases its armature upon the subsequent removal of thereceiver from the switchhook by subscriber A, the short circuit isremoved from the high resistance right-hand winding of relay 24. Relay2% thereupon operates, connecting the interrupter 29 in circuit with itslow resistance left-hand Winding and the lamp 22. The lamp is thereuponintermittently lighted. The operator upon observing the intermit tentglow of lamp 22 will actuate listening key 28 to connect the operatorstelephone set with the cord circuit. Upon the actuation of the key 28,contact 27 is opened, whereupon relay 23 releases to disconnect theinterrupter from circuit relation with lamp 22.

The operator upon receiving instructions from subscriber A may have thedesired connection completed in any desired manner.

\Vhat is claimed is:

1. A telephone exchange system comprising telephone lines, a linkcircuit for interconnecting the lines, a supervisory relay in the linkcircuit responsive to the opening and closure of a telephone line, alocal relay energized over a circuit independent of the supervisoryrelay upon connection of the link circuit with one of the lines anddeenergized upon response of the supervisory relav when the line isopened, a relay energized upon the deenergization of the local relay, asignaling device, and interrupter mechanism brought into circuit withthe signaling device by the subsequent energization of the local relayupon the closure of the line.

2. A telephone exchange system comprising telephone lines, a linkcircuit connected with one of the lines, a supervisory relay in the linkcircuit responsive to the opening and closure of the connected line, alocal circuit relay deenergized upon response of the supervisory relaywhen the connected line is opened, a third relay normally deenergizedwhile the local relay is energized. and energized upon thedeenergization thereof, a signaling device, and interrupter mechanismbrought into circuit with the signaling device by the subsequentenergization of the local relay when the connected line is closed.

3. A telephone exchange system comprising telephone lines, a linkcircuit connected with one of the lines, a supervisory relay in the linkcircuit responsive to the opening and closure of the connected telephoneline, a local circuit relay deenergized upon response of the supervisoryrelay when the line is opened, a slow-to-operate relay energized uponthe deenergization of the local relay, a signaling device, andinterrupter mechanism brought into circuit with the signaling device bythe subsequent energization of the local relay upon the closure of theline while the slow-to-operate relay is energized.

4:. A telephone exchange system comprising telephone lines, a linkcircuit connected with one of the lines, a supervlsory relay in the linkcircuit responsive to the opening and closure of the connected telephoneline, a local relay deenergized upon the response of the supervisoryrelay when the line is opened, a slow-to-operate relay energized uponthe deenergization of the local relay, a locking circuit for theslow-tooperate relay established upon the energization thereof, asignaling device, interrupter mechanism, and a circuit for the signalingdevice and interrupter mechanism established by the subsequentenergization of a local relay and including contacts of both theslow-to-operate and the local relay.

5. A telephone exchange system comprising telephone lines, a linkcircuit connected with one of the lines, a supervisory relay in the linkcircuit responsive to the opening and closure of the connected telephoneline, a local relay, deenergized upon the response of the supervisoryrelay when the line is opened, a slow-to-operate relay energized uponthe de'e'nergization of the local relay, a locking circuit for theslow-to-operate relay established upon the energization thereof, asignaling device, interrupter mechanism, and a circuit for the signalingdevice and interrupter mechanism completed by the subsequentenergization of the local relay upon the closure of the connectedtelephone line and including engaged contacts of the slowto-operate andlocal relays and a winding of the local relay.

6. A telephone exchange system comprising a telephone line, a linkcircuit for c0nnecting with the telephone line, a supervisory relay inthe link circuit responsive to the opening and closure of the telephoneline, a local circuit relay energized upon the connection of the linkcircuit with the telephone line, a short circuit for the local relaycompleted by the energization of the supervisory relay upon the openingof the line thereby deenergizing the local relay, a slowto-operate relayenergized upon the deonergization of the local relay, a signalingdevice, and interrupter mechanism brought into circuitwith the signalingdevice by the subsequent energization of the local relay upon thedeenergization of the supervisory relay when the line is closed.

7. A telephone exchange system comprising a telephone line, a linkcircuit for connecting with the telephone line, a supervisory relay inthe link circuit responsive to the opening and closure of the telephoneline, a local circuit relay energized upon the connection of the linkcircuit with the telephone line, a short circuit for the local-relaycompleted by the energization of the supervisory relay upon the openingof the line thereby denergizing the local relay, a slowto-operate relayenergized upon the deenergization of the local relay, a signaling device, interrupter mechanism, and a circuit for the signaling device andinterrupter mechanism completed by the subsequent en ergization of thelocal relay when the line is closed and including contacts of both theslow-to-operate and local relays.

8. A telephone exchange system comprising a telephone line, a linkcircuit for connecting with the telephone line, a supervisory relay inthe link circuit adapted to be controlled over the telephone line whenconnected With the link circuit, a local circuit relay energized uponthe connection of the link circuit with the telephone line anddeenergized upon the energization of the supervisory relay when the lineis opened, an operators telephone set, a listening switch for connectingthe operators telephone set with the link circuit, a slow-to-operaterelay energized upon the deenergization of the local relay, a lockingcircuit for the slow-tooperate relay completed upon the energizationthereof and including a contact of the listening switch, a signalingdevice, and interrupter mechanism brought into circuit with thesignaling device by the subsequent energization of the local circuitrelay when the telephone line is closed.

In witness whereof I hereunto subscribe n1y7na1ne this 21st day ofSeptember, A. D. 191

RAY S. WILBUR.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

